Method and apparatus for making end closures for tubular containers



Nov/25,1947. BQGQSLQWSKY 2,431,537

METHOD AND APPARATUS FOR MAKING END CLOSURES FOR TUBULAR CONTAINERS Filed Jan. 25, 1945 2 Sheets-Sheet 1 B. 'BOGOSLOWSKY Nov. 25, 1947. 2,431,537

METHODIAND APPARATUS FOR MAKING END CLOSURES FOR TUBULAR CONTAINERS Filed Jan. 25, 1945 2 Sheets-Sheet 2 inHHHHHHHH IHHHHHMMHMMI U HHHHHHHHW J n v INVENTOR Z/lfi ww ATTORNEY wall and the neck, thus smoothing said folds and improving their appearance.

Mounted in the passage 6 of the die is a plunger 8 having rack teeth 9 adapted to engage the pinion IE! which may be rotated by lever II to move the plunger along the passage. Thus, while continuing to apply longitudinal pressure to the mandrel and die, the plunger is moved upwardly to apply heavy pressure to the material of the neck 4 which is confined in the closed end of the passage 6. Such pressure reforms and compresses the twisted material of the neck to form a relatively short button I2 of compressed material which is tightly sealed by the pressure applied. Said button has a thickness substantially in excess of the thickness of the tubular wall, and is compressed and compacted into a mass of substantial strength and rigidity. In the p eferred embodiment illustrated said button protrudes outwardly somewhat, but the depression 3 in the end of the mandrel is preferably of a depth equal to or greater than the thickness of the button, so that in the finished closure the bottom of the button is flush with or recessed within the bottom rim 13 of the container, so that the container may stand upright on a flat surface. Alternatively, however, the mandrel may be recessed, in which case the compressed button protrudes inwardly somewhat.

I have found that the material of the neck may be sufiiciently compressed by pressure alone to provide a button in which the folds of the material are so tightly compacted as to form a leak proof closure. In this connection, it will be noted that all of the end edges of the tubular blank are collected together during the preforming operation and are located within the twisted neck structure, so that when this structure is subjected to pressure, as described, all of the passages through which leakage might otherwise occur are efiectively closed.

However, in cases Where the tubular blank consists of or includes thermoplastic materials, the invention does not preclude the use of heat in addition to pressure to heat seal such thermoplastic material, if desired. For example, heat may be applied in the region of the button only, as by heating the plunger 8, or if it is desired to heat seal the folds which extend inwardly from the rim of the container to the button, the end of the mandrel or the surface I of the die, or both, may be heated.

In Figures 7 to 10, I have illustrated the invention as it may be applied to the provision of an end closure for a tubular blank 20 in which the opposite end has been previously provided with a shoulder and a somewhat constricted dispensing neck 2| adapted to receive a closure cap. Such shoulder and neck may be formed in any desired manner, as for example, by the methods and apparatus disclosed in my copending applications Serial No. 550,238, filed August 19, 1944, or Serial No. 548,895, filed August 10, 1944-. In such cases, it is not possible to place the tubular blank on a mandrel, as previously described, and while the method employed in forming the closure is essentially the same as that previously described, the apparatus used in carrying out the method must be adapted to the absence of said mandrel.

Thus, as before, the first step of the method is to fold the end portionsof the tubular blank 2| inwardly, and then to twist them together to form an elongated neck 22. Preferably, in order to be able to form a smooth rim, a tubular member 23 is inserted within the tubular blank prior to the folding operation so that the end edges of the tubular member may define the fold line of the rim when the end portions of the tubular blank are folded inwardly.

Such tubular member may conveniently be allowed to remain in the finished container, in which case it provides increased strength and rigidity for the tubular wall, and in cases where such tubular member is to be allowed to remain in the finished container, the material of the tubular member may be selected with reference to the contents of the container. Thus, if the container is to be used to package dry material such as coffee, for example, the tubular member might be made of cardboard or paper. On the other hand, if the container is to be used to package a liquid, a material should be selected which is not affected by and which does not itself affect such liquid.

Alternatively, the tubular member may, if desired, be removed from the container after it is completed. In this case a tubular member of resilient material such as thin spring steel wound in convolute form may be employed. After the container is completed, such a tubular member 'may be collapsed and withdrawn through the dispensing neck previously referred to.

After the tubular blank has been preformed in the manner described, it is inserted in a die set comprising a lower block 24 and an upper block 25. The block 24 has a central passage 26 adapted to receiv the elongated neck 22 and has a surface 2? shaped to give the desired depressed conformation to the bottom end wall of the container. The upper block 25 comprises a tubular portion which fits into an annular groove in the upper portion of the block'24, so that when the die parts 24, 25 are brought together, as shown in Figure 9, the end of the tubular portion rests against the shoulder 28.

The die block 25 also contains an annular ring 2&3 having a surface which conforms to the shape of the upper end of the tubular blank and is held in yielding engagement therewith by means of a spring so which is placed under compression when the die blocks 24, 25 are brought together, thus applying controlled pressure to the tubular wall, and causin the lower rim of the wall to seat against the bottom of the die cavity. The die block 25 is also provided with a centrally located longitudinal spindle 3| of a diameter small enough to enter the dispensing neck 2 l, but of a diameter and length sufiicient to tightly close the end of the passage 26 when the die blocks are brought together.

After the die blocks are brought together as shown in Figure '9, longitudinal pressure is applied to the die set as by placing the same in a press, to lock the tubular blank firmly in position. Then heavy pressure is applied to the material of the neck, as previously described, using the lever 32 to operate the plunger 33 through pinion 3 5 and rack teeth 35 as before. 1 As previously described, such pressure reforms and compresses the material to form a button 35 of compressed material of the nature previously described.

It will be understood that the invention may be variously modified and embodied Within the scope of the subjoined claims.

I claim as my invention:

1. The method of making an end closure for a tubular container which comprises preforming the end portions of a tubular blank to form an end wall and a neck protruding outwardly therefrom with all of the end edges of said blank collected together in said neck, and applying pressure to said neck longitudinally thereof to compress and compact the same to form a button of substantial strength and rigidity.

2. The method of making an end closure for a tubular container which comprises preforming the end portions of a tubular blank to form an end wall and a neck protruding outwardly therefrom with all of the end edges of said blank collected together in said neck, confining said neck in a die passage, applying pressure to the portions of said end wall surrounding said die passage, and then applying pressure to said twisted neck to compress and compact the same to form a button of substantial strength and rigidity.

3. The method of making an end closure for a tubular container which comprises folding the end portions of a tubular blank inwardly, twisting said inwardly folded portions together to form an elongated twisted neck, and applying pressure to said twisted neck longitudinally thereof to compress and compact the same to form a button of substantial strength and rigidity.

4. The method of making an end closure for a tubular container which comprises folding the end portions of a tubular blank inwardly, twisting said inwardly folded portions together to form an elongated twisted neck, confining said neck in a die passage, applying pressure to the portions of said blank surrounding said die passage, and then applying pressure to said twisted neck to compress and com-pact the same to form a button of substantial strength and rigidity.

5. Apparatus for making an end closure for a tubular container from a tubular blank having a preformed end portion consisting of an end wall and a neck protruding axially therefrom,

comprising, in combination a die block having a cavity adapted to receive said preformed end portion and a passage adapted to receive said neck, means to close one end of said passage to confine said neck therein, and means to apply pressure to the confined neck to reform and compress the same,

6. Apparatus for making an end closure for a tubular container from a tubular blank having a preformed end portion consisting of an end wall and a neck protruding axially therefrom, comprising, in combination, a die block having a cavity adapted to receive said preformed end portion and a passage adapted to receive said neck, a second die block adapted to receive the other end of said tubular blank, said second die block carrying a member extending through said tubular blank and closing one end of said passage to confine said neck therein, and means to apply pressure to the confined neck to reform and compress the same.

BORIS BOGOSLOWSKY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 722,881 Paine Mar. 17, 1903 808,520 Driskell Dec. 26, 1905 1,058,523 Auchu Apr. 8, 1913 1,093,605 Burdick Apr. 21, 1914 1,123,976 Auchu Jan. 5, 1915 1,853,191 Benke Apr. 12, 1932 

